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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Natural Disaster Database Design and Development for Himalaya Using Social Media</article-title>
      </title-group>
      <contrib-group>
        <aff id="aff0">
          <label>0</label>
          <institution>Kiran Zahra Department of Geography</institution>
          ,
          <addr-line>UZH Winterthurerstr. 190, 8057 Zurich</addr-line>
          ,
          <country country="CH">Switzerland</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2016</year>
      </pub-date>
      <fpage>14</fpage>
      <lpage>17</lpage>
      <abstract>
        <p>Ever increasing population of social media and increasing trend of sharing information related to several different topics has the great potential to use this information for different purposes such as disaster management. The use of Volunteered Geographic Information (VGI) has its own challenges because of the unstructured nature of social media such as extracting information out of noise and credibility related issues. This project focusses on the core issues of using user generated content for disaster management in developing countries.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>Frequency and impact of natural disasters is on
the rise worldwide (Kellenberg &amp; Mobarak, 2008 ;
Whybark, 2007). For more than fifty years,
researchers have focused on a series of vital
questions such as human occupancy of hazard
zones, response of people and societies, and how to
lessen the effects of environmental hazards (Cutter,
2012). A well-structured database about natural
disasters can better answer these questions and can
be an efficient source of analysing causes, effects,
capacity, vulnerability and further planning of
disaster management such as EM-DAT1.</p>
      <p>The Himalayas are the youngest mountain range
in the world. This mountain range is still
geologically active (Lavé &amp; Avouac, 2000), which
causes a high occurrence of natural disasters in this
region. Documenting natural disasters is important
in order to understand current issues and future
predictions. Although this kind of information is
available, it is technically incomplete and difficult
to maintain.</p>
      <p>People share a bulk of information on social
media sites such as Twitter during mass
emergencies (Hossmann et al., 2011 ; Terpstra et
al., 2012). Information shared on social media is
not only usable, but also very valuable in terms of
its contents (Kavanaugh &amp; Yang, 2011). In case of
disaster in a region the most important information
for disaster response organizations are location,
timing and impact (Jongman et al., 2015). Social
media has the potential to serve in all these aspects.</p>
      <p>The increasing trend of using smart phones and
accessibility to fast internet connections are the
main causes of rapid growth of social media
population (Kwak et al., 2010). Social media users
such as Twitter community tend to share bulk of
tweets publicly available and these tweets have
great potential to extract meaningful information
and use this information during emergency events.
But it is often very difficult to filter only “useful
information” from the Twitter stream by making
keyword based queries and thus it is recommended
to use machine leaning algorithms to filter
information (Sakaki, Okazaki, &amp; Matsuo, 2013).</p>
      <p>
        Credibility of information shared on social media
is another challenge to using this type of data
during disasters. Mendoza, Poblete, &amp; Castillo
(
        <xref ref-type="bibr" rid="ref5 ref9">2010</xref>
        ) state in their research that rumours tend to
be questioned more than authentic news and
propose a framework to deal with credibility
issues.
      </p>
      <p>Gelernter &amp; Balaji (2013) discuss the increased
use of geographical content in tweets during
disasters. This geographic location information can
be used to manage rescue operations during and
after disasters and also for generating maps.
Although disaster relief is very important issue, but
no research has done on utilizing VGI to design and
create natural disaster database.</p>
      <p>Overall aim of this study is to analyse different
aspects of disaster related information shared on
Twitter about any disaster happening in Himalayan
region and its surrounding countries. This social
media data has the potential to contain helpful
geographic information and situational updates
during mass emergency events. These can be used
by disaster response agencies for efficient
management. This research will help to investigate
the issues brought about by natural hazard
phenomena.</p>
      <p>The objectives of this research are to:
• Apply machine learning algorithms to
resolve keyword ambiguities and optimize tweet
classification</p>
      <p>• Assess credibility of tweets based on data
quality standards of tweets shared during disasters
• Analyse the granularity of geographic
features reported in tweets during disasters,
geoparsing and geocoding those geographic
features to display on the map for visual
representations</p>
      <p>• Conceptualize and implement a VGI based
natural disaster database
2</p>
    </sec>
    <sec id="sec-2">
      <title>State of the art</title>
      <p>Sakaki, Okazaki, &amp; Matsuo (2013) discussed
‘semantic analysis of tweets’ in their research.
They did this analysis to detect target events from
tweets. They also mentioned that identifying
keywords alone from tweets about disasters is not
enough to gather valuable information about the
event. Verma et al. (2011) studied tweets
‘contributing to situational awareness’ and tweets
‘not contributing to situational awareness’. They
used examples of tweets discussing the disaster but
not contributing to situational awareness, as they
do not give any actionable information.</p>
      <p>Acar and Muraki (2011) argue that it is often very
difficult to filter correct information out of the
Twitter data stream. Uncontrollable informal
retweets question the certainty and reliability of
Twitter in disaster situations because during a
disaster credibility of information is very
important. Semantic analysis of tweets and
keyword ambiguities have very little or no research
about tweets originating from Himalayan region
and its surrounding countries, moreover the role of
geographic features has never been studied in
Naïve Bayes classification efficiency.</p>
      <p>Twitter streaming Application Program Interface
(API) downloads many fields called metadata of
tweet with tweet text field. This metadata can be
used to effectively assess tweet credibility (Canini,
Suh, &amp; Pirolli, 2011). Credibility assessment issues
are expected to be more complex due to cultural
and language diversity in the Himalayan region.</p>
      <p>When there is a disaster, precise location
identification is a very important element in many
situations. Disaster/emergency response
organizations can only respond if they know
precise locations. People tend to add location
information when they share something about
disasters on social media. Lingad, Karimi, &amp; Yin
(2013) discuss a tool “Named Entity Recognizers”.
They state that location extraction from microblogs
is becoming more accurate and that such tools have
great potential to find out locational information
more correctly.</p>
      <p>Social media’s application to disaster
management is getting more and more important
because of its real-time nature such as
TweetTracker (Kumar et al., 2011), Artificial
Intelligence for Disaster Response (AIDR) (Imran
et al., 2014), Twitcident (Abel et al., 2012),
ScatterBlogs for situational awareness (Thom et
al., 2015).</p>
      <p>Since forecasting disaster is difficult, efficient
disaster management is very important to improve
disaster response. There are many national and
international organizations maintaining records of
natural disasters such as EM-DAT, a famous global
natural and technological disaster database. Such
databases are created and maintained by data
collected from different primary and secondary
data sources. Witham (2005) discussed in his
research various issues about completeness and
accuracy of maintaining databases about disasters.
He also presented a new database about volcanic
disasters and analyse this information for risk
management.</p>
      <p>The role of social media as a great potential
source of data during disasters has already been
discussed, this research focusses on using
information shared on Twitter to design a VGI
based database. Designing and developing VGI
based databases is a novel concept for the
Himalayan region. This research gap formulated
the following research questions:</p>
      <p>RQ 1: Which data mining techniques are
successful in identifying relevant tweets
originating from developing countries?</p>
      <p>RQ 2: Does information shared on social media
meet quality indicators for user generated content
(UGC) to use in case of disasters in the Himalaya
region?</p>
      <p>RQ 3: What is geographic feature granularity in
UGC during disasters?</p>
      <p>RQ 4: What are the potential contributions of
social media data in designing and developing VGI
based disaster database for the Himalaya region?
3</p>
    </sec>
    <sec id="sec-3">
      <title>Methods</title>
      <p>Twitter offers free, real-time data (tweets)
downloads through its streaming API. This API
requires certain parameters to capture tweets such
as particular keywords, tweets sent from particular
users, or tweets originating from a particular
region. For this research, an application has been
designed in R to capture real-time tweets without
any pause, based on disaster-related keywords such
as flood, earthquake, and landslide. Starting from
25.4.2015 more than 25 Million tweets based on
disaster-related keywords have been downloaded
so far. The supervised Naïve Bayes topic model is
used to classify tweets in two classes:
“information” and “not information”.</p>
      <p>The Twitter streaming API downloads tweets
with their metadata. In addition to the tweet text
field, forty-one associated fields are also
downloaded. Many researchers have identified
different sets of features to assess the credibility of
tweets. Features such as the “number of followers,
retweet count, number of URL’s, verified, time,
user description, status count, [and] length of a
tweet” (Canini, Suh, &amp; Pirolli, 2011; Morris et al.,
2012) will be used to assess the credibility of
tweets in the Himalayan region.</p>
      <p>A natural disaster event will be selected as a case
study to analyse the granularity of geographic
features reported during the event. These
geographic features then later be geoparsed and
geocoded by available online platforms such as
address-parser and gisgraphy. Geoparsing is the
process of automatically identifying geographical
information (names of places) from text (Gelernter
&amp; Balaji, 2013). Geocoding is the process of
converting text into geographical coordinates
(Ratcliffe, 2004). The spatial information
identified from the tweets will be displayed on the
map. This map is expected to reveal complex
locations patterns about social media user’s way of
reporting locations during disasters.</p>
      <p>Tweet text with its metadata will be analysed to
identify potential attributes and entities to design
an Entity Relationship Diagram (ERD). This
analysis will be performed on adequate subset of
acquired data. Designed ERD will be used for
development of the database.
4</p>
    </sec>
    <sec id="sec-4">
      <title>Conclusion</title>
      <p>This research project has great potential to be
implemented by disaster response agencies within
the Himalayan region and also by international
organizations by adapting during and post-disaster
framework. The Himalayan region is important in
determining world climate, prone to frequent
hazards, and is generally less accessible due to a
lack of facilities and resources. This research can
be a good platform to minimize the impact of
disasters in this region. This research project
enriches the Geographic Information Science
methods and concepts by focusing on unique
spatio-temporal phenomena of natural disasters.
5
•
•
•</p>
      <p>Acar, Adam and Muraki, Y. (2011).
Twitter for crisis communication : lessons
learned from Japan’ s tsunami disaster.
7(3), 392–402.</p>
      <p>
        Adam, N. R., Shafiq, B., &amp; Staffin, R.
(
        <xref ref-type="bibr" rid="ref17">2012</xref>
        ). Spatial computing and social
media in the context of disaster
management. IEEE Intelligent
Systems, 27(6), 90-96.
      </p>
      <p>Bilham, R., Gaur, V., &amp; Molnar, P. (2001).
Pollen Tubes Labeled With Green
Fluorescent Protein Show That the Pollen
•
•
•
•
•
•
•
•</p>
      <p>Tube Also Pen- Etrates an, (August),
1442–1444.</p>
      <p>
        Canini, K. R., Suh, B., &amp; Pirolli, P. L.
(2011). Finding Credible Information
Sources in Social Networks Based on
Content and Social Structure. 2011 IEEE
Third Int’l Conference on Privacy,
Security, Risk and Trust and 2011 IEEE
Third Int’l Conference on Social
Computing, 1–8.
http://doi.org/10.1109/PASSAT/SocialCo
m.2011.91
Clay Whybark, D. (2007). Issues in
managing disaster relief inventories.
International Journal of Production
Economics, 108(
        <xref ref-type="bibr" rid="ref1">1–2</xref>
        ), 228–235.
http://doi.org/10.1016/j.ijpe.2006.12.012
Cutter, Sussan L., (
        <xref ref-type="bibr" rid="ref17">2012</xref>
        ). Hazards,
vulnerability and environmental justice.
New York, NY: Taylor and Francis
Earle, P. S., Bowden, D. C., &amp; Guy, M.
(2011). Twitter earthquake detection:
Earthquake monitoring in a social world.
Annals of Geophysics, 54(6), 708–715.
http://doi.org/10.4401/ag-5364
Gelernter, J., &amp; Balaji, S. (2013). An
algorithm for local geoparsing of
microtext. GeoInformatica, 17(4), 635–
667.
http://doi.org/10.1007/s10707-0120173-8
Hossmann, T., Carta, P., Schatzmann, D.,
Legendre, F., Gunningberg, P., &amp; Rohner,
C. (2011). Twitter in Disaster Mode:
http://doi.org/10.1145/2079360.2079367
Jongman, B., Wagemaker, J., Romero, B.,
&amp; de Perez, E. (
        <xref ref-type="bibr" rid="ref15">2015</xref>
        ). Early Flood
Detection for Rapid Humanitarian
Response: Harnessing Near Real-Time
Satellite and Twitter Signals. ISPRS
International Journal of Geo-Information,
4(4), 2246–2266.
http://doi.org/10.3390/ijgi4042246
Kattelmann, R. (2003). Glacial Lake
Outburst Floods in the Nepal Himalaya: A
Manageable Hazard? Retrieved December
21, 2015, from
http://download.springer.com/static/pdf/9
38/art%3A10.1023%2FA%3A102113010
1283.pdf?originUrl=http://link.springer.c
om/article/10.1023/A:1021130101283&amp;to
•
•
•
•
•
•
•
•
1192.
http://doi.org/10.1080/1369118X.2011.61
1815
Murthy, D., &amp; Longwell, S. A. (2013).
Twitter and Disasters. Information,
Communication &amp; Society, 16(6), 837–
855.
http://doi.org/10.1080/1369118X.2012.69
6123
Nasikhin, &amp; Adriani, M. (2007). Location
Identification for the Geographic
information Retrieval.
      </p>
      <p>
        Petrović, S., Osborne, M., &amp; Lavrenko, V.
(
        <xref ref-type="bibr" rid="ref5 ref9">2010</xref>
        ). Streaming first story detection
with application to twitter. NAACL HLT
2010 - Human Language Technologies:
The 2010 Annual Conference of the North
American Chapter of the Association for
Computational Linguistics, Proceedings
of the Main Conference, (June), 181–189.
Retrieved from
http://www.scopus.com/inward/record.url
?eid=2-s2.080053272732&amp;partnerID=tZOtx3y1
Poblete, B., Castillo, C., &amp; Mendoza, M.
(2011). Information Credibility on
Twitter, 45–59.
      </p>
      <p>
        Ratcliffe, J. H. (2004). Geocoding crime
and a first estimate of a minimum
acceptable hit rate. International Journal
of Geographical Information Science,
18(January), 61–72.
http://doi.org/10.1080/136588103100015
96076
Richardson, S. D., &amp; Reynolds, J. M.
(2000). An overview of glacial hazards in
the Himalayas. Quaternary International,
65–66, 31–47.
http://doi.org/10.1016/S10406182(99)00035-X
Sadler, J. C., &amp; Ramage, C. S. (1976). The
Role of Mountains in the South Asian
Monsoon Circulation. Journal of the
Atmospheric Sciences.
http://doi.org/10.1175/15200469(1976)033&lt;2255:COROMI&gt;2.0.CO;
2
Sakaki, T., Okazaki, M., &amp; Matsuo, Y.
(2013). Tweet analysis for real-time event
detection and earthquake reporting system
•
•
•
•
•
•
•
•
development. IEEE Transactions on
Knowledge and Data Engineering, 25(4),
919–931.
http://doi.org/10.1109/TKDE.2012.29
Singh, A. (
        <xref ref-type="bibr" rid="ref5 ref9">2010</xref>
        ). Climate Change and
Disasters in the Hindu Kush Himalayan
Region. Article, New Delhi, India:
Solution Exchange. Retrieved from
http://amritapeoplesvoice.blogspot.com
Terpstra, T., Stronkman, R., Vries, a De,
&amp; Paradies, G. L. (
        <xref ref-type="bibr" rid="ref17">2012</xref>
        ). Towards a
realtime Twitter analysis during crises for
operational crisis management.
Proceedings of ISCRAM 2012, (April), 1–
9.
      </p>
      <p>
        Thayyen, R. J., &amp; Gergan, J. T. (
        <xref ref-type="bibr" rid="ref5 ref9">2010</xref>
        ).
Role of glaciers in watershed hydrology: a
preliminary study of a “Himalayan
catchment.” The Cryosphere, 4(1), 115–
128. http://doi.org/10.5194/tc-4-115-2010
Verma, S., Vieweg, S., Corvey, W. J.,
Palen, L., Martin, J. H., Palmer, M., …
Anderson, K. M. (2011). Natural
Language Processing to the Rescue ?:
Extracting “ Situational Awareness ”
Tweets During Mass Emergency.
      </p>
      <p>
        Vieweg, S., Hughes, A. L., Starbird, K., &amp;
Palen, L. (
        <xref ref-type="bibr" rid="ref5 ref9">2010</xref>
        ). Microblogging during
two natural hazards events. Proceedings of
the 28th International Conference on
Human Factors in Computing Systems
CHI ’10, 1079.
http://doi.org/10.1145/1753326.1753486
Viviroli, D., &amp; Weingartner, R. (2004).
The hydrological significance of
mountains: from regional to global scale.
Hydrology and Earth System Sciences,
8(6), 1017–1030.
http://doi.org/10.5194/hess-8-1017-2004
Witham, C. S. (2005). Volcanic disasters
and incidents: A new database. Journal of
Volcanology and Geothermal Research,
148(3–4), 191–233.
http://doi.org/10.1016/j.jvolgeores.2005.0
4.017
Yamada, T., &amp; Sharma, C. (1993). Glacier
lakes and outburst floods in the Nepal
Himalaya. IAHS
PublicationsPublications of …, (218), 319–330.
Retrieved from
      </p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          ken2=exp=1450710999~acl=/static/pdf/9 38/art%253A10.
          <source>1023%252FA%253A102 1 Kavanaugh</source>
          ,
          <string-name>
            <given-names>A.</given-names>
            , &amp;
            <surname>Yang</surname>
          </string-name>
          ,
          <string-name>
            <surname>S.</surname>
          </string-name>
          (
          <year>2011</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          <source>Microblogging in crisis situations :</source>
          ,
          <fpage>1</fpage>
          -
          <lpage>6</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          (
          <year>2008</year>
          ).
          <article-title>Does rising income increase or decrease damage risk from natural disasters</article-title>
          ?
          <source>Journal of Urban Economics</source>
          ,
          <volume>63</volume>
          (
          <issue>3</issue>
          ),
          <fpage>788</fpage>
          -
          <lpage>802</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          http://doi.org/10.1016/j.jue.
          <year>2007</year>
          .
          <volume>05</volume>
          .003 Kwak,
          <string-name>
            <given-names>H.</given-names>
            ,
            <surname>Lee</surname>
          </string-name>
          ,
          <string-name>
            <given-names>C.</given-names>
            ,
            <surname>Park</surname>
          </string-name>
          ,
          <string-name>
            <given-names>H.</given-names>
            , &amp;
            <surname>Moon</surname>
          </string-name>
          , S.
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          (
          <year>2010</year>
          ).
          <article-title>What is Twitter , a Social Network or a News Media?</article-title>
          <source>The International World Wide Web Conference Committee (IW3C2)</source>
          ,
          <fpage>1</fpage>
          -
          <lpage>10</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          http://doi.org/10.1145/1772690.1772751 Lavé,
          <string-name>
            <given-names>J.</given-names>
            , &amp;
            <surname>Avouac</surname>
          </string-name>
          ,
          <string-name>
            <surname>J. P.</surname>
          </string-name>
          (
          <year>2000</year>
          ).
          <article-title>Active folding of fluvial terraces across the Siwaliks Hills, Himalayas of central Nepal</article-title>
          .
          <source>Journal of Geophysical Research</source>
          ,
          <volume>105</volume>
          (
          <issue>B3</issue>
          ),
          <fpage>5735</fpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          http://doi.org/10.1029/1999JB900292 Lingad,
          <string-name>
            <given-names>J.</given-names>
            ,
            <surname>Karimi</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            , &amp;
            <surname>Yin</surname>
          </string-name>
          ,
          <string-name>
            <surname>J.</surname>
          </string-name>
          (
          <year>2013</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          <article-title>Location extraction from disaster-related microblogs</article-title>
          .
          <source>WWW 2013 Companion - Proceedings of the 22nd International Conference on World Wide Web</source>
          ,
          <fpage>1017</fpage>
          -
          <lpage>1020</lpage>
          . Retrieved from http://www.scopus.com/inward/record.url ?eid=
          <fpage>2</fpage>
          -
          <lpage>s2</lpage>
          .
          <fpage>0</fpage>
          -
          <lpage>84892685783</lpage>
          &amp;partnerID=tZOtx3y1 Mendoza,
          <string-name>
            <given-names>M.</given-names>
            ,
            <surname>Poblete</surname>
          </string-name>
          ,
          <string-name>
            <given-names>B.</given-names>
            , &amp;
            <surname>Castillo</surname>
          </string-name>
          ,
          <string-name>
            <surname>C.</surname>
          </string-name>
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          (
          <year>2010</year>
          ).
          <article-title>Twitter Under Crisis : Can we trust what we RT </article-title>
          ?,
          <fpage>71</fpage>
          -
          <lpage>79</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          <string-name>
            <surname>Middleton</surname>
            ,
            <given-names>S. E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Middleton</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Modafferi</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          (
          <year>2014</year>
          ).
          <article-title>Real-time crisis mapping of natural disasters using social media</article-title>
          .
          <source>IEEE Intelligent Systems</source>
          ,
          <volume>29</volume>
          (
          <issue>2</issue>
          ),
          <fpage>9</fpage>
          -
          <lpage>17</lpage>
          . http://doi.org/10.1109/MIS.
          <year>2013</year>
          .126 Morris,
          <string-name>
            <given-names>M. R.</given-names>
            ,
            <surname>Counts</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            ,
            <surname>Roseway</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            ,
            <surname>Hoff</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            , &amp;
            <surname>Schwarz</surname>
          </string-name>
          ,
          <string-name>
            <surname>J.</surname>
          </string-name>
          (
          <year>2012</year>
          ).
          <article-title>Tweeting is believing?</article-title>
          <source>Proceedings of the ACM 2012 Conference on Computer Supported Cooperative Work - CSCW '12</source>
          ,
          <fpage>441</fpage>
          -
          <lpage>450</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          http://doi.org/10.1145/2145204.2145274 Murthy,
          <string-name>
            <surname>D.</surname>
          </string-name>
          (
          <year>2013</year>
          ).
          <article-title>NEW MEDIA AND NATURAL DISASTERS: Blogs and the 2004 Indian Ocean tsunami</article-title>
          .
          <source>Information Communication and Society</source>
          ,
          <volume>16</volume>
          (
          <issue>7</issue>
          ),
          <fpage>1176</fpage>
          - http://ks360352.kimsufi.com/redbooks/a2 18/iahs_218_
          <fpage>0319</fpage>
          .pdf Imran,
          <string-name>
            <given-names>M.</given-names>
            ,
            <surname>Castillo</surname>
          </string-name>
          ,
          <string-name>
            <given-names>C.</given-names>
            ,
            <surname>Lucas</surname>
          </string-name>
          ,
          <string-name>
            <given-names>J.</given-names>
            ,
            <surname>Meier</surname>
          </string-name>
          ,
          <string-name>
            <surname>P.</surname>
          </string-name>
          , et al. (
          <year>2014</year>
          )
          <article-title>AIDR: Artificial intelligence for disaster response</article-title>
          .
          <source>In: Proceedings of the companion publication of the 23rd international conference on World wide web companion. [Online].</source>
        </mixed-citation>
      </ref>
      <ref id="ref12">
        <mixed-citation>
          2014 pp.
          <fpage>159</fpage>
          -
          <lpage>162</lpage>
          . Available from: doi:10.1145/2567948.2577034.
        </mixed-citation>
      </ref>
      <ref id="ref13">
        <mixed-citation>
          &amp; Liu,
          <string-name>
            <surname>H.</surname>
          </string-name>
          (
          <year>2011</year>
          )
          <article-title>TweetTracker: An Analysis Tool for Humanitarian and Disaster Relief</article-title>
          . In: Fifth
          <source>International AAAI Conference on Weblogs and Social Media</source>
          .
          <year>2011</year>
          pp.
          <fpage>661</fpage>
          -
          <lpage>662</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref14">
        <mixed-citation>
          <string-name>
            <surname>Thom</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kruger</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Ertl</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Bechstedt</surname>
            ,
            <given-names>U.</given-names>
          </string-name>
          , et al. (
          <year>2015</year>
          )
          <article-title>Can twitter really save your life? A case study of visual social media analytics for situation awareness</article-title>
          .
        </mixed-citation>
      </ref>
      <ref id="ref15">
        <mixed-citation>
          <source>In: 2015 IEEE Pacific Visualization Symposium (PacificVis)</source>
          . [Online].
          <year>2015</year>
          pp.
          <fpage>183</fpage>
          -
          <lpage>190</lpage>
          . Available from: doi:10.1109/PACIFICVIS.
          <year>2015</year>
          .
          <volume>7156376</volume>
          .
        </mixed-citation>
      </ref>
      <ref id="ref16">
        <mixed-citation>
          <string-name>
            <surname>Abel</surname>
            ,
            <given-names>F.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Hauff</surname>
            ,
            <given-names>C.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Houben</surname>
          </string-name>
          , G.-J.,
          <string-name>
            <surname>Stronkman</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          , et al. (
          <year>2012</year>
          )
          <article-title>Twitcident: Fighting fire with information from social web streams</article-title>
          .
          <source>In: Proceedings of the 21st international conference companion on World Wide Web - WWW '12 Companion.</source>
        </mixed-citation>
      </ref>
      <ref id="ref17">
        <mixed-citation>
          [Online].
          <year>2012</year>
          p.
          <fpage>305</fpage>
          . Available from: doi:10.1145/2187980.2188035.
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>